<footer>
    <div>
        <p>版权所有 &copy; MY DEAR DEER</p>
    </div>
</footer>

<style>
    footer{
        position: fixed;
        bottom:0;
        left:0;
        width:100%;
        background:#222;
        color:#fff;
        height:50px;
        z-index: 3;
    }
    footer div p{
        text-align: center;
        height:50px;
        line-height:50px;
        font-size:20px;
    }
</style>